Rhododendron rootstock named &#39;Rhodunter 37&#39;

ABSTRACT

A new and distinct  Rhododendron hybrid  plant used as a rootstock that exhibits hardy and vigorous growth.

BOTANICAL CLASSIFICATION

[0001]Rhododendron hybrid

VARIETAL DENOMINATION

[0002] ‘Rhodunter 37’

BACKGROUND OF THE INVENTION

[0003] The present invention comprises a new and distinct cultivar of Rhododendron hybrid used as a rootstock known by the varietal name ‘Rhodunter 37’. The new variety was discovered at the Institute for Ornamental Plant Breeding, Ahrensburg, Germany. The new variety is the result of a planned breeding program between unpatented Rhododendron fortunei×cv. ‘Cunningham's White’. The new variety has been trial and field tested and has been found to retain its distinctive characteristics and remain true to type through successive propagations.

DESCRIPTION OF THE DRAWINGS

[0004] The accompanying photographic drawings illustrate the new variety, with the color being as nearly true as is possible with color illustrations of this type.

[0005]FIG. 1 shows a side perspective view of a typical flowering plant of the new variety grown to a flowering plant; and

[0006]FIG. 2 shows a close-up view of the inflorescences of the new variety.

DESCRIPTION OF THE PLANT

[0007] The following detailed description sets forth the characteristics of the new cultivar. The data which defines these characteristics were collected by asexual reproductions carried out at the Institute for Ornamental Plant Breeding in Ahrensburg, Germany. The color readings were taken in natural daylight. Color references are primarily to the R.H.S. Colour Chart of The Royal Horticultural Society of London.

PLANT

[0008] Type: Evergreen shrub.

[0009] Use: Rootstock.

[0010] Soil: Sandy loam.

[0011] Light: Full.

[0012] Fruit bearing: Very low.

[0013] Crop time: 1.5 years is required to achieve finished product size that is ready for use as a rootstock.

[0014] Dimensions at crop time (3 years after grafting. Dimensions depend on the vigor of the scion cultivar):

[0015]Height.—50 cm.

[0016]Length.—40 cm.

[0017] Vigor: 120% of standard using ‘Nova Zembla’ as the standard.

[0018] Habit: Erect.

[0019] Hardiness: USDA zone 6a.

[0020] Rooting habit: Compact root bales.

[0021] Time to initiate roots: 3 months at 22-25° C. for softwood cuttings.

[0022] Disease and pest resistance: None.

[0023] Trunk (at 4 years):

[0024]Diameter.—3 cm.

[0025]Height.—5 cm above soil.

[0026]Bark color.—Surface: Grey-brown. Flesh: Grey-brown.

[0027]Lenticels.—Inconspicous.

[0028] Branches:

[0029]Color.—Surface: Grey-brown. Flesh: Grey-brown.

[0030]Internode length.—1-2 cm.

[0031]Branching angle at emergence.—45° angle.

[0032]Habit.—Compact.

[0033]Pubescence.—Absent.

[0034]Branch lenticels.—Inconspicous.

[0035] Leaves:

[0036]Arrangement.—Alternate.

[0037]Length.—13 cm maximum.

[0038]Width.—4 cm maximum.

[0039]Shape.—Oblanceolate.

[0040]Apex.—Broad.

[0041]Base.—Tapering.

[0042]Color.—Adaxial: 147A. Abaxial: 147C.

[0043]Surface.—Adaxial: Glabrous. Abaxial: Glabrous.

[0044]Margins.—Entire.

[0045]Division.—Undivided.

[0046]Petiole.—Length: 2 cm. Width: 2 mm. Color: 144A. Surface: Glabrous.

[0047]Leaf stipules.—Sessile.

[0048]Leaf pubescence.—Absent.

[0049]Venation pattern.—Feather-veined.

[0050]Vein color.—Adaxial: 144A. Abaxial: 145C.

[0051]Leaf texture.—Hard.

[0052]Leaf appearance.—Typical Rhododendron leaf.

[0053] Fruit: Fruits (capsules) are usually absent due to self-sterility or incompability with other Rhododendrons. When present, the seed color is 164B.

[0054] Flower:

[0055]Arrangement.—Truss.

[0056]Shape.—Widely funnel-shaped.

[0057]Bud.—Width: 20 mm. Length: 40 mm. Color: Closed: 186B. Bursting: 75B. Time of bloom: At 2 years old. Lastingness of bloom: 21 days.

[0058]Diameter.—8 cm.

[0059]Depth.—20 mm.

[0060]Bloom quantity.—13-17 per truss.

[0061]Number of petals.—7.

[0062]Petals.—Fused.

[0063]Petal margin.—Undulate.

[0064]Flower color when fully opened.—Upper surface: 69B. Lower surface: 69A.

[0065]Peduncle.—Length: 4 cm. Width: 3 mm. Surface: Glabrous.

[0066] Natural flowering season: Beginning of May through the end of May.

[0067] Fragrance: Inconspicuous.

REPRODUCTIVE ORGANS

[0068] Stamens:

[0069]Number.—14.

[0070]Length.—30 mm.

[0071]Color.—150D.

[0072] Anthers:

[0073]Shape.—Normal Rhododendron type.

[0074]Color.—158B.

[0075]Length.—25 mm.

[0076]Width.—1 mm.

[0077]Amount of pollen.—Medium.

[0078]Color of pollen.—150D.

[0079]Stigma color.—145A.

[0080] Pistils:

[0081]Length.—5 cm.

[0082] Style:

[0083]Color.—159D.

[0084]Length.—45 mm.

[0085]Width.—1 mm.

[0086] Ovaries:

[0087]Length.—5 mm.

[0088]Width.—3 mm.

[0089]Color.—137C.

[0090]Position.—Superior. 

I claim:
 1. A new and distinct variety of Rhododendron hybrid plant used as rootstock substantially as shown and described. 